what is the “modem sound”? is that actually the noise the modem makes as a machine or some kind of thing someone “made up” kinda like the telephone ring?
Modems don’t really make sounds, and telephone lines don’t carry sound. Phone lines simply carry an electric signal. WIth a telephone, the signal is generated by a microphone, and with a modem, it’s generated by modulating data. The modem sound is simply what happens when you put that modulated data signal through a speaker instead of a voice.
Modems, by convention, turn their internal speaker on when connecting as a form of user feedback, and then turn them off when the connection negotiation is complete.
If you are talking about the “squeal” when the modems are connecting, the sounds are specific, and serve a definite purpose.
They allow the modems to signal each other, exchange information about their respective capabilities, and then test the current connection for the maximum workable speed supported by the two modems.
If you listen to different speed modems, and turn on and off options such as data compression and reliable connections, you will hear the differences between the various kinds of handshaking and negotiation that goes on.
After a while, listening to the “squeal” can help you troubleshoot modem problems.
After the modems negotiate a connection, the sound settles down to a fairly steady hiss. This is the actual data being sent back and forth.
You know you’re a computer geek when:
You are puzzled by other people’s complaint about the modem’s connection noise. That’s not noise, that’s information!
Sometimes when I´m logging in and I hear the modem sound it brings back memories of my first computer, a Sinclair ZX Spectrum, now gather around kids and I shall tell you of the age when computers used audio tapes to store and load programs, you would sit there by the tape recorder for about 30 minutes listening to the stream of blazing bytes loading (48Kb, maximum) and if there was as much as a glitch in the tape the darn thing wouldn´t load, and you had to tune the reading head to try to minimize noise, and… well, you get the pictures; those where the days when men were nerds and women were nowhere to be seen. 
A modem is a “Modulator/Demodulator.” Let’s say you want to convert a digital signal which only has 2 states (off and on), into something that can be carried over a phone line. When the signal is “off” then you send out a tone of say 1000 Hz and when the signal is “on” then you send out a tone of say 5000 Hz. This is called modulating the signal to voice frequencies. You’re ear can hear about 100 Hz to 20,000 Hz, so both of these tones are well within the human hearing range. In fact they have to be, since the phone signals are specifically designed for human voice, which has a smaller bandwidth than what the human ear can hear.
At the other end, you need to demodulate the signal, so you have a receiver that puts out an “off” signal when it picks up a tone of 1000 Hz and an “on” signal when it picks up a tone of 5000 Hz. Voila. You’ve made a simple modem system.
As the digital bits change states from off and on, the tone changes rapidly from a lower pitched tone to a higher pitched tone. We can easily hear these tones, and they sound like modem screech to our ears.
Modem standards these days are a bit more complicated than what I just wrote, but that’s the basic idea.
Forgot to mention, the reason that you can hear any of it at all is because someone chose to put a speaker on the modem. Otherwise the signals would only be on the phone line. As ftg said, that’s not noise, that’s information! It’s so geeks like myself can figure out what’s going wrong when something isn’t working right. Just by listening to the screeches I can tell things like when the modem got a busy signal, when it’s having trouble with the signal, and roughly what speed it’s connecting at. Since the average user just hears meaningless shrieking noises, many modern modems have an option where you can turn off the speaker.
if the OP is answered can i hijack for abit?
can the terminatrix thing work? can you literally speak and listen through the phone meaningfully if you can do modem language?
The speaker is useful for non-geeks too. You can hear the modem using tones to dial the number - that’s how the telephone communicates with the switchboard machine. And if you input the wrong dial-up number, instead of the beeping and screeching you’ll hear a confused “Hello??” or a “We’re sorry, this number is…”.
I don’t think a human can generate a modem signal. We can’t even generate the dialing tone because each tone is made up of two frequencies. (Hey, I wonder if a guitar or piano can…)
Favorite part about modem ‘noise’ is when I used to say “What noise is your modem making?” and either record the call, or put it on speaker to entertain me and my tech support buds back in the mid 90’s.
Somehow made the utterly appalling existence of help desk a tiny bit more tolerable.
The modem at your end needs to talk to the modem at the other end but first they have to agree on the protocol (language). That process is called “handshaking”. Your modem dials the other modem and waits for a response. The other modem answers by putting a carrier on the line. from that point on they both keep proposing different protocols until they can agree on one. Once they agree the speaker is turned off as it is not useful to the user but while they are connecting the user can know more or less what’s happening if something goes wrong. Did the other side respond? you can hear that and it gives you an indication of what may be the problem if you cannot get a connection. You can know if the other modem has certain capabilities like 56K. etc.
I find it amusing that the same people who always said that the US government should only be concerned with US interests (screw the UN and the rest of the world) are now so concerned with liberating the Iraqis from Saddam Hussein.
I loathed president Clinton but I liked his choice for Secretary of State, Madelaine Albright who I always found had a pretty good perspective on international politics. I can say the same today: I loathe president Bush but I like Colin Powell and I wish Bush had listened to Powell and not to Rumsfeld.
Here’s what Ms. Albright has to say now:
I agree with her.
If it were a regular phone she was using, I don’t see why it wouldn’t be possible (once you’ve accepted that shape shifting cyborgs from the future exist). The big problem is that she is using a cell phone. Cell phones digitize and compress voice data before sending it over the line, so while it’s possible to send data over a cell phone, it can’t be done by simply connecting a modem to a cell phone. It would have been more plausible if the cell phone in T3 had data service, and the T-X simply plugged in to it.
Sigh, you can’t even have a talk about modems around here without someone having drag Clinton through the dirt…
From the geek-history department :- back in the old,old, days, (when I were a lad) ,modems used to communicate at much lower speeds, starting off at 300 baud a second. That’s 30 characters a second, and pretty slow.
When I was a stripling young engineer, I had a very old colleague whose party trick was putting a speaker on the phone line when the 300 baud modems were communicating (not just handshaking) and calling out the characters they were sending in real time, as they were sent, by listening to the tones. If they were sending an email, for example he’d recite out all the header information, byte by byte, then the actual contents.
And that’s how I learned that anyone can eavesdrop on un-encrypted modem communications.
I usually prepare my posts in notepad and then just cut and paste to avoid losing posts as often happens is you prepare them online. Obviously, I posted that to the wrong thread by mistake and I immediately reported it to the mods in the hope if would get deleted without further comment. Oh well.